@Raycu They are a very nasty invasive species in the specific of Japan. In 1960 the mayor of Chicago donated them to Emperor Akihito (who was still crown prince at the time), who then proceeded to spread them among local fisheries, but they escaped and utterly wrecked the local fauna, especially in Lake Biwa. Ever since, bluegill trade is prohibited in Japan.
Ehhh, as invasive species go, fish never got me too excited. Once we overfish the whole place it doesn't matter which ones were supposed to be there before we ate them all . . .
(note: deadpan gallows humour; dunno if we have an emoji for that but anyway not to be taken seriously)